“Identify the incompetent teachers and those that are coasting.” These words from the new head of Ofsted, Sir Michael Wilshaw, threw me into a panic. I’m not incompetent, but am I coasting?

I would have thought that if you like coasting, you’re not going to be in this job. Yesterday, I coasted through a pre-school staff briefing, a broken photocopier, early-morning playground duty (which involved breaking up a fight and all the subsequent paperwork that now involves), a maths lesson, a 20-minute assembly which I led in front of 400 children, and an hour of English. I then coasted through a lunch hour spent hunting down the key to the games locker, sorting out my photocopying from the morning and eating half a cheese sandwich while walking down a corridor.

In the afternoon, I coasted through a blur of science, reading groups and sorting out some post-lunchtime friendship squabbles. When the bell finally went for the end of the day, there was just an hour’s netball practice followed by classroom tidying and planning for the next day before the caretaker shooed me homewards, where I coasted through marking 120 books.

In none of my lessons did anyone shout “Eureka!” or stand on their desk and proclaim “O Captain, my Captain”. Most of them learnt something; everyone produced some work. At no point could I have worked harder or moved faster. If we taught every day as if Ofsted were in the room, we would drop dead with exhaustion. It would be like driving as if constantly taking your test. Worryingly, I get the feeling this is what we’re now expected to do.

I’m sure there are plenty of teachers out there who, for whatever reason, are not teaching effectively. Surely they need guidance and support and, if all else fails, help in finding an alternative career?

Yet you hear very little mention of support in the Ofsted chief’s rhetoric. His comments, along with the new performance-management guidelines that come into place next year, effectively ensure that teachers are now ineffective unless proven otherwise.

And how will this call to seek out the coasters affect the power-loving head with their own agenda? The new breed of headteacher, under pressure to raise standards, is constantly at war with their staff. To them Sir Michael’s message is akin to tapping Senator McCarthy on the shoulder and asking if he would mind rounding up some Communists.

The truth is that some excellent teachers will become ineffective under this approach. It’s an isolated job where it’s easy to feel paranoid and insecure about your abilities. You very rarely see anyone else teach, training courses seem to be vanishing, and you’re constantly bombarded with changes to policy and the curriculum. Between fighting the kids, the parents and the senior management, praise is rare.

I’ve got a mug on my desk that says “World’s Best Teacher”. It’s a regular end-of-term present for hundreds of teachers. I normally stash them at the back of my cupboard, but I’m keeping this one close. Under the head of Ofsted’s new regime, it might be the only accolade left to cling to.

The writer works in a primary school in Nottingham. To tell us what keeps you awake at night email david.marley@tes.co.uk.